The Douglas County Treasurer’s Office will mail real estate and personal property tax bills Thursday.

The first half of the payments are due Dec. 20. Because that day falls on a Sunday this year, the deadline is extended to Dec. 21, a Monday. Payments must be either made or postmarked by that date.

The second half of the 2009 bills are due May 10, 2010. Taxpayers can make payments online — although it includes a processing fee.

Checks or money orders made payable to “Douglas County Treasurer” need to be sent to P.O. Box 668, Lawrence 66044. A return envelope is provided with the bill.

These office locations also accept payments:

• From 8 a.m. to 5 p.m. weekdays, Douglas County Courthouse, 1100 Mass.

• From 8 a.m. to 5 p.m. weekdays, the Park Plaza Shopping Center, 2108 W. 27th St., Suite I.

• Dillons, 3000 W. Sixth St., 7 a.m. to 6 p.m. every Tuesday through Friday.

• Baldwin City Market, 112 W. Eighth St., Baldwin City, 8 a.m. to 11 a.m. and noon to 4 p.m., Dec. 14 to Dec. 18.